Soil Properties, Soil Erosion and Conservation, Nutrition Types and Nutrient Compounds, Nutrition in Green Plants, Nutrition in Mammals, Transport in Plants, Transport in Animals

Senior 2: Term 1 - Theme: Soil

Topic 2.1: Physical and Chemical Properties of Soil

* **Composition:** Mineral Matter (45%), Organic Matter/Humus (5%), Soil Water (25%), and Soil Air (25%). * **Texture:** Relative proportion of sand, silt, and clay. **Loam** is the most desirable balance. * **Water/Air Characteristics:** * **Sandy Soil:** Large particles, poor water retention, fast drainage, good aeration. * **Clay Soil:** Small particles, very high water retention, poor drainage (waterlogged), poor aeration. * **Loam Soil:** Mixed particles, good water retention, moderate drainage, good aeration. * **Chemical Properties:** * **pH:** Affects nutrient solubility. Plants prefer slightly acidic to neutral soil (pH 6.0–7.0). Lime is used to reduce acidity. * **Nutrients:** Plants require Macronutrients (N, P, K) and Micronutrients (trace amounts like Iron, Zinc, Copper).

Topic 2.2: Soil Erosion and Conservation

* **Erosion:** The removal and transport of topsoil by Water, Wind, or Human Activity (deforestation, overgrazing, poor farming). * **Effects:** Reduced fertility/crop yields, siltation of water bodies, and formation of gullies. * **Conservation Methods:** * **Afforestation:** Planting trees to bind soil. * **Contour Ploughing:** Tilling across slopes to slow runoff. * **Terracing:** Creating flat steps on steep slopes. * **Strip Cropping:** Planting alternating strips of different crops. * **Mulching:** Covering soil with organic residue to protect from impact and reduce evaporation.

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Term 2: Nutrition in Plants and Animals

Topic 3.1: Nutrition Types and Compounds

* **Types:** * **Autotrophic:** Synthesizing food from inorganic substances (e.g., Photosynthesis). * **Heterotrophic:** Feeding on other organisms (Holozoic, Saprotrophic, Parasitic). * **Major Nutrient Compounds:** * **Carbohydrates:** Energy source. * **Proteins:** Growth and repair. * **Lipids:** Energy storage and insulation. * **Vitamins/Minerals:** Metabolism and health. * **Water/Fibre:** Transport/solubility and digestive health.

Topic 3.2: Nutrition in Green Plants

* **Photosynthesis:** $6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$ (using light and chlorophyll). * **Leaf Adaptations:** Large surface area, thin lamina, stomata for gas exchange, and veins for transport.

Topic 3.3: Nutrition in Mammals

* **Digestion:** The breakdown of insoluble food into soluble molecules via enzymes. * **Digestive Tract:** Mouth (mechanical/chemical) → Oesophagus (peristalsis) → Stomach (protein digestion) → Small Intestine (main digestion/absorption) → Large Intestine (water absorption) → Anus (egestion). * **Balanced Diet:** Contains all essential nutrients. Malnutrition leads to conditions like Kwashiorkor (protein), Scurvy (Vitamin C), and Anaemia (Iron).

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Term 3: Transport in Plants and Animals

Topic 4.1: Transport in Plants

* **Absorption:** Water via osmosis and minerals via active transport through root hairs. * **Transpiration:** Water loss via stomata creates "transpiration pull" to move water up the **Xylem**. * **Translocation:** Movement of sucrose from source to sink via the **Phloem**.

Topic 4.2: Transport in Animals

* **Circulatory System:** Uses a double circulation system to move blood through the heart twice per circuit. * **Blood Vessels:** * **Arteries:** High pressure, thick walls, carry blood away from the heart. * **Veins:** Low pressure, contain valves, carry blood toward the heart. * **Capillaries:** One cell thick, site of exchange. * **Blood Components:** Plasma (transport), Red Blood Cells (Oxygen transport), White Blood Cells (immunity), and Platelets (clotting).

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